Dear Sha-niece:
There is no magic number, like 19, that makes you ready for the world. There are people of all ages not ready for the world. It is not an easy world, so it takes a lot of time to get used to it.
Start with small steps, one small step at a time, take it and then wait for a moment, see how it feels, where you stand, if you like where you stand and what next step will it make sense to take.
anita